Circuit-interrupting device



June 25, 1929. J. A. SPENCER CIRCUIT IITERRUPTING DEVICE Original Filed Feb. 26, 1925 INVENTOR John /1. Spencer ATTORNEY III! WITNESSES: 4 1

Patented June 25, 1929.

UNITED STATES PATENT OFFICE.

JOHN SPENCER, OF REVERE, MASSACHUSETTS, ASSIGNOR T SPENCER THERMO- STAT COMPANY, OF CAMBRIDGE, MASSACHUSETTS, A CORPORATION OF MASSA- CHUSETTS.

cmcurr-mrnmwrrme DEVICE.

Application filed February 26, 1925, Serial No. 11,751. Renewed February 21, 1928.

material, of different diameters, located thereon, and a plurality of contact plates located against said discs and held thereagainst by means projecting through said circular plates and discs. A thermostatic disc having a plurality of contact bridging members mounted thereon, is supported by a threaded rod projecting through and supported by the tubular clamping member and adjustable relatively thereto.

In the single sheet of drawings,

Figure 1 is a top plan view of a switch mechanism embodying my invention, parts thereof being cut away,

taken on the line II-II of Fig. 1,

Fig. 3 is a fragmentary sectional view therethrough, taken on the line IIIIII of Fi 1,

igi l is a top'plan view of a supporting plate device,

Fig. 5 is a sectional view thercthrough, taken on the line,V-V of Fig. 4,

Fig. 6 is a bottom plan view of the parts shown in Fig. 4, 1 s

Fig. 7 is a top plan view of an insulating assembly and Fig. 8 is a sectional view therethrough, taken on the line VIIIVIII of Fig. 7.

A switch mechanism designated generally by the numeral 11, is illustrated in top plan view in Fig. 1 of the drawing, and comprises a bottom supporting plate 12, a top supporting plate13, each having a central aperture therethrough, within which there is located a tubular clamping member 14. The clamping member 14 is providedwith an annular shoulder at the bottom thereof and is made substantially longer than the combined thickness of the two plates 12 and 13, to secure the two plates in proper operative position in face to face relation. The peri hery of the upper end of the tubular member 14 is compressed to provide an annular portion 15 Fig. 2 isa view in section therethroughf overhanging the top plate 13 in substantially the manner illustrated in Fig. 5 of the drawing.

The plate 12 is provided with a plurality of spaced openings 16, and the plate 13 is two members being provided with central axial openings 22 therethrough to receive a metal memben23, of tubular shape, that is provided at one end thereof with an annular shoulder 24 and that has the other end portion' thereof turned over as illustrated by the numeral 25 in Fig. 8 of the drawing to securely clamp the two discs in coaxial and closely adjacent positions relatively to each other. The discs 21 and 19 are preferably made of mica and, when secured together by the use of the tubular member or thimble 23, they may be considered as an insulating member assembly that is easily handled.

The disk 19 is provided with a plurality of openings 26 therein, that are so spaced as to be coaxial with the openings 16 and 17 in the supporting plates 12 and 13 in one position of the insulating-member assembly peripherally of the supporting plate aggregate. A plurality of contact plates 27, 28, 29 and 31 are operatively supported by the supporting plate assembly and are located against the outer surface of the disk 19. The contact plates 27 to 31, inclusive, are of substantially arcuate shape, the inner edges thereof having such radii that they operatively engage the outer periphery of the disk 21, andany turning movement in the plane of the contact plate is prevented thereby.

Means for securing the respective contact plates against the supporting plate and the insulating-plate assembly comprises rivet members 32 having an enlarged head 33, and extending through the respective coaxial openingsi16 and-17 in the plates 12 and 13, a disk 34 of electric insulating material, such as mica, serving to insulate the head 33 from the plate 13, and serving also to position the.

to register with an opening The switch of the present construction is more particularly applicable to, and employed with, thermostatic actuating means for effecting the control of the energizing circuit of an electrically heated device. A ther mostatic disc 35 that comprises two metals having relatively different temperature ex pansivities is adjustably mounted in substantially parallel-spaced relation to the supporting plate assembly. This mounting comprises a shouldered screw-threaded stud 36 that projects through the internally screwthreaded tubular clamping member 14 and that has a flanged member 37 located close to one end thereof. A fixed nut 38 is provided adjacent to, but spaced from, the flange 37 and the disc 35 is loosely mounted the rebetween to permit of a turning movement of the stud 36 relatively to the internally screw threaded tubular member 14 to permit of varying the distance of the thermostatic disc and of other members carried thereby toward and away from the contact plates hereinbefore described.

The end of the stud 36 is provided with a portion 39 of reduced thickness that may be made of substantially rectangular form in section, in order to permit of holding the stud 36 while a lock-nut 41 is tightened to prevent any further turning movement of the stud 36 after proper adjustment has once been made.

A plurality of contact bridging members 42 are supported by the thermostatic disc 35, by means of a stud member 43 that has an intermediate portion v of enlarged diameter which fits against a disk 44 of electric-insulating materi. i, such as mica. A disc 45 of electrio-insulating material is so located against a surface 35 0f the thermostatic disc 35 as 46 therein, through which a portion 43 of the stud 43 may extend. A small metal disc 47 is located against the outer surface of the disc 45 both bf which register with the portion 43. An end portion 43? of the stud member 43 may be peened over in order to securely clamp the contact bridging member in its proper operative position, relatively not only to the thermostatic disc, but also to the spaced ends of the fixed contact plates which it is to operatively engage. The disc member 47 is slightly dished inwardly during the peening operation which effects a location of the intermediate portion of the stud43 coax'ially with the opening 46 through which it projects.

The contact bridging members 42 are loose- 1y mounted on the lowerportion of the studs 43, as is more particularly disclosed and claimed in my copending application, Serial No. 565,255, filed June 1, 1922, and assigned to the Spencer Thermostat Company.

The contact plates 27 and 31, are not secured in their proper operative position by means of short rivets as are theplates28 and 29, but by theuse of studs that have a depending projection 48 to permit of connecting thereto the ends of suitable supply circuit conductors in a manner well known in the art. In all other respects, the studs 48 are of the same general construction and have the same effect as the rivets 32. r

In order to insure that the thermostatic disc 35 shall not move circumferentially relatively to the supporting plate, a locating means is provided, which comprises a stud l'lflVlIlg an enlarged lower portion 49 that fits into coaxial aligned openings 51 and 52 provided in the respective plates 13 and 12. To hold the member 49in its proper operative position relatively to the plates 12 and 13, a punch member is employed to head-over the rim portion thereof that is located in substantially the same planeas the upper. surface of the plate 13, as is more particularly illustrated in Fig. 2 of the drawing. The member 49 has a portion 53 of relatively smaller diameter than the lower portion projecting upwardly therefrom and through an opening 54 in the disc 19 and through an opening 55 inthe thermostatic disc 35.

The thermostatic disc 35 is provided with a non-developable surface, substantially .as de scribed in my U. S. Letters Patent No. 1,448,240, such. that when the disc is subjected to a predetermined temperature, the un- I equal expension of the metals comprising the disc causes it to suddenly reversethe curvature of-its non-developable surface to thereby disengage the contact bridgingmembers 42 from the contact members 27, 28, 29, and 31, simultaneously. Upon cooling of the disc 35 to a. predetermined temperature, the un equal contraction of the metals comprising the disc causes it to suddenly assume its initial position, as illustrated in Fig. 2 of the drawings.

The device embodying my invention thus provides a relatively small supporting-plate assembly and an insulating disc assembly which cooperate with each other to support a plurality of'contact plates of arcuate form in proper operative positions against one surface of an insulating disc of larger diameter and against the outer periphery of an insulatingdisc of smaller diameter. Small insulating discs located in openings in the lower of a pair of "supporting plates, serve also to properly position the securing means coaxially in the openings and supported by the metal supporting plates.

It is evident that any turning movement interrupted at six contact points.

of the contact plates in the plane of the plates themselves, is etfectivel prevented by the operative engagement 0 the inner periphery surface thereof with the insulating disc of smaller diameter.

The device embodying my invention, provides also relatively simple means for operatively supporting a plurality of contact bridging members that are normally in operative engagement with the contact plates in such manner that adjustment thereof toward and away from the contact plates is easily effected, whereby, in the present construction, it is possible to vary the temperature at which the thermostatic disc will operate to interrupt the circuit through the plurality of contact plates.

While not hereinbefore specifically mentioned, it may be here stated that this switch mechanism provides av circuit interrupting means whereby the circuit is simultaneously That is, the current path is over the plate 27 and through the operating bridging member and the plate 28, from there through the cooperating bridging member to plate 29 and from there to a cooperating bridging member to the plate 31 and to the other conductor of the supply circuit. 7

Since various modifications and changes may be made herein without departing from ing plates in the spirit and scopethereof, all such modifi cations are intended to be covered by the appended claims. I

I claim as my invention:

1. A switch comprising a pair of supporting plates in face-.to-face relation, a tubular clamping member for holding said plates together, a plurality of contact plates insulatedly mounted on said supporting plates, a plurality of contact bridging members normally operatively engaging said contact plates, and means projecting through said clamping member for operatively supporting said con tact bridging members.

2. A switch comprising a pair of supportface-to-face relation, a tubular clamping member for holding said plates together, a plurality of contact plates insulatedly mounted on said supportin plates, a plurality of contact bridging mem ers normally operatively engaging said contact plates, and means adjustably supported by said clan'iping member for operatively supporting said contact bridging members.

3. A switch comprising a pair of supporting plates in face-to-face relation, a tubular clamping member for holding said plates together, a plurality of contact plates insulatedly'mounted on said supporting plates, a plurality of contact bridging members normally operatively engaging said contact plates, and means for adjusting the same towardand away from said contact members.

4. A switch comprising a plurality of supporting plates, a tubular clamping member for holding said plates together, a plurality of discs of electric-insulating material and of different external diameter located against the outer face of one of said supporting plates, a plurality of contact plates of substantially arc-uate contour located on the insulating disc of larger diameter and abutting the periphery of the smaller disc, a plurality of contact bridging members normally operatively engaging said contact plates, and means projecting through and supported by said tubular clamping member for normally operatively supporting said contact bridging members. I

5'. An electric switch comprising a base of a plurality of layers of metal, means for clamping said layers together, an electricswitching mechanism, and means cooperating with said clamping means for supporting said switching means.

6. An electric switch comprising a base composed of a plurality of layers, stationary.

contacts insulatedly mounted thereon, clampa plurality of movable contacts, thermostatic ing means for holding said layers together,

means for actuating said contacts, and means cooperating with said clamping means for supporting said thermostatic means.

7. A switch comprising a laminated base having stationary contacts thereon, means for holding said laminations together, a movable thermostatic member carrying aplurality of contacts, and means cooperating with said holding means for supporting said member on said base.

8. The device of claim 7 wherein said cooperating means may be adjusted.

9. A thermostatically controlled switch comprising a plurality of cooperating stationary and movable contacts, a thermostatic element, said movable contacts being mounted on said element, cooperating contacts being adapted to be simultaneously opened and closed, a metal base in heat conducting relation to said element, and means for insulatedlloy mounting said stationary contacts on said use.

In testimony whereof, I have hereunto subscribed my name this 20th day of February, 1925. 

